陶瓷粉体催化臭氧化降解水中苯酚

将陶瓷粉末应用于降解苯酚废水用臭氧化催化剂,表征了陶瓷的化学组成、0电荷pH和表面羟基密度,并考察了反应条件的影响.结果表明,陶瓷粉末对于臭氧化降解质量浓度为100mg·L-1的模拟苯酚废水具有较为显著的催化效果.不同温度的影响试验表明,在278～308 K时,苯酚的降解速率随温度升高而加快,然而(与单独臭氧化比较)在较低温度下陶瓷的催化效果更加显著.结合羟基自由基清除剂的影响试验,推断在催化臭氧化过程中臭氧分子和羟基自由基共同氧化污染物,陶瓷粉末的表面羟基促进了臭氧分子到羟基自由基的转变,因而加快了臭氧化过程.     

酸处理活性炭催化臭氧氧化肉桂醛为苯甲醛

以经酸处理的活性炭为催化剂,进行多相催化臭氧氧化肉桂醛为苯甲醛。考察了溶剂种类、乙醇用量、活性炭用量、臭氧流量及臭氧化反应温度对反应的影响。结果表明,活性炭能够明显提高臭氧的利用率,臭氧利用率从单独使用臭氧时的53.5%提高到67.4%。最佳反应条件为:无水乙醇为溶剂,m(无水乙醇)/m(肉桂醛)=3,氧气流量为800 mL/min(臭氧流量为0.71 g/h),m(活性炭)/m(肉桂醛)=0.01,在0℃下臭氧化反应2 h,然后进行还原反应,苯甲醛收率为44.0%。     

MnO_2/γ-Al_2O_3催化剂的制备及催化臭氧氧化苯酚废水

以γ-Al_2O_3为载体,Mn(NO_3)_2·4H_2O为前驱体,制备MnO_2/γ-Al_2O_3非均相负载型催化剂。以臭氧为氧化剂,MnO_2/γ-Al_2O_3为催化剂,催化臭氧氧化降解100 mg/L的苯酚模拟废水,考察活性组分负载量、焙烧温度、焙烧时间对催化臭氧降解苯酚的影响。结果表明,锰负载量10%,焙烧温度500℃,焙烧时间5 h为MnO_2/γ-Al_2O_3催化剂较佳的制备方案。将其应用到高碱性苯酚溶液中,在臭氧浓度为0.96 mg/L,催化剂用量为2 g/L,温度25℃,反应60 min时,苯酚和COD的去除率分别达到97.6%和71.8%,催化活性较好。     

臭氧化合成乙醛酸技术研究 Ⅱ.马来酸酯臭氧化过程

对马来酸酯臭氧化合成乙醛酸的技术进行了研究,重点考察了臭氧化过程中的工艺参数对反应的影响。获得优化的工艺条件为,马来酸酯臭氧化反应的适宜温度应小于-5℃,臭氧浓度约30gO3/m3时,马来酸酯浓度为6~10g/100mL。通过后续的催化加氢还原和水解,获得高纯度的乙醛酸产品,总收率达到80%以上。     

臭氧化合成乙醛酸技术研究Ⅱ.马来酸酯臭氧化过程

对马来酸酯臭氧化合成乙醛酸的技术进行了研究,重点考察了臭氧化过程中的工艺参数对反应的影响.获得优化的工艺条件为,马来酸酯臭氧化反应的适宜温度应小于-5℃,臭氧浓度约30gO3/m3时,马来酸酯浓度为6～10g/100mL.通过后续的催化加氢还原和水解,获得高纯度的乙醛酸产品,总收率达到80%以上.     

臭氧化合成乙醛酸技术研究Ⅱ．马来酸酯臭氧化过程

对马来酸酯臭氧化合成乙醛酸的技术进行了研究,重点考察了臭氧化过程中的工艺参数对反应的影响.获得优化的工艺条件为,马来酸酯臭氧化反应的适宜温度应小于-5℃,臭氧浓度约30gO3/m3时,马来酸酯浓度为6～10g/100mL.通过后续的催化加氢还原和水解,获得高纯度的乙醛酸产品,总收率达到80%以上.     

MnO_2/γ-Al_2O_3催化剂的制备及催化臭氧氧化苯酚废水

以γ-Al_2O_3为载体,Mn(NO_3)_2·4H_2O为前驱体,制备MnO_2/γ-Al_2O_3非均相负载型催化剂。以臭氧为氧化剂,MnO_2/γ-Al_2O_3为催化剂,催化臭氧氧化降解100 mg/L的苯酚模拟废水,考察活性组分负载量、焙烧温度、焙烧时间对催化臭氧降解苯酚的影响。结果表明,锰负载量10%,焙烧温度500℃,焙烧时间5 h为MnO_2/γ-Al_2O_3催化剂较佳的制备方案。将其应用到高碱性苯酚溶液中,在臭氧浓度为0.96 mg/L,催化剂用量为2 g/L,温度25℃,反应60 min时,苯酚和COD的去除率分别达到97.6%和71.8%,催化活性较好。     

超声波改性强化Mn/AC催化臭氧化降解苯酚效能分析

为提高臭氧氧化降解含酚废水的效能,对载体活性炭进行超声改性,并利用浸渍沉淀法制备Mn/AC催化剂,通过BET、SEM、EDS、XRD表征分析超声处理对其结构的影响,同时用苯酚模拟废水考察超声改性对其去除效能的影响。结果表明,超声改性起到清灰造孔作用,载体孔道增多,比表面积和孔体积增高,强化了负载,Mn的负载量由2. 40%升至3. 85%并以MnO2形式存在,增大分散度;超声改性增强了催化剂的吸附及催化臭氧化能力,提高体系的吸附-催化臭氧氧化协同效应,Mn/U60-AC+O3体系在催化剂质量浓度为2 g/L、苯酚初始质量浓度为100 mg/L、温度为(25±1)℃、臭氧质量浓度为3 mg/L、气体通入流量为4 m L/min、pH=10、水体积为1 L的条件下反应24 min,苯酚的去除率高达99. 64%,比Mn/AC+O3体系提高了16%。     

新生态MnO2／凹凸棒土复合催化剂对苯酚臭氧化反应的催化作用

利用化学法合成了新生态MnO2／凹凸棒土复合催化荆，对模拟苯酚废水进行了臭氧化处理，考察了不同条件对苯酚催化臭氧化过程的影响。结果表明，复合催化荆对体系臭氧化过程中苯酚的降解和COD的去除有显著的促进作用，含催化剂时反应动力学受体系pH值的影响程度明显减小。在pH=8．0的条件下，催化剂投加量以500mg／L为宜。适当操作条件下，体系COD的最高去除率可达85．3％。     

光催化真空紫外-臭氧氧化一体的反应器研制

自行研制了集光催化真空紫外及臭氧氧化为一体的反应器,并采用正交实验考察其对苯酚的降解性能。结果表明,其对苯酚的矿化速率常数分别是单独真空紫外光氧化(VUV)、光催化(UV/V-N-TiO_2)的3.01和2.10倍,分别是组合真空紫外光催化(VUV/V-N-TiO_2)、真空紫外臭氧氧化(VUV/O_3)和光催化臭氧氧化(UV/V-N-TiO_2/O_3)的1.48、2.08和2.60倍,三者形成协同促进作用矿化苯酚效果好。苯酚初始质量浓度对其矿化性能影响最大,越低矿化效果越好。在初始苯酚质量浓度10 mg/L、循环体积流量0.5 L/min、p H为4、空气体积流量0.2 L/min的优化条件下,反应4 h矿化率达92.6%。一体反应器结构紧奏、工艺简单。     

吸附法处理含酚模拟废水的实验研究

研究了活性炭纤维(简称ACF)处理含酚模拟废水的静态吸附最佳工艺条件，测定了不同温度下的吸附等温线，并在相同条件下比较了ACF和活性炭的吸附性能。结果表明，ACF对苯酚的吸附容量为248mg／g，吸附饱和后经多次再生吸附容量几乎不变，吸附性能比活性炭好。室温时，在酸性或中性条件下，向100mL浓度282mg／L的含酚模拟废水投加活性炭纤维0．5g，恒温振荡30min，苯酚去除率可达91％。     

臭氧氧化双酚A的性能及机理

采用臭氧氧化法在动态条件下降解双酚A,考察了臭氧浓度、水样进水流速、pH、双酚A初始浓度及温度对氧化降解双酚A效果的影响,探究了臭氧氧化双酚A的反应机理。结果表明,臭氧对溶于水中的双酚A具有良好的去除效果,在反应条件(臭氧浓度11.04 mg/L、水样进水流速2 mL/min、原水pH=6.83、双酚A初始浓度10 mg/L、温度40℃)下,去除率达86.12%。增加臭氧浓度或适当升高温度可增加臭氧氧化双酚A去除率。pH和进水流速的提高会降低双酚A去除率。偏酸性条件下,臭氧降解双酚A的效果更好。臭氧氧化双酚A反应活化能较低,属于快速反应。臭氧浓度不变,增加双酚A初始浓度会使其去除率减小。臭氧氧化双酚A以臭氧直接氧化为主,同时也存在羟基自由基间接氧化。     

石墨毡作为粒子电极处理含酚废水的试验研究

采用石墨毡作为三维电极中的粒子电极,处理模拟苯酚废水,研究对比了不同阳极材料、粒子电极填充方式、初始pH值、槽电压、电极极性交替对苯酚降解效果的影响。电化学测试和电解试验结果表明,相比于304不锈钢和Ti/IrO_2-RuO_2电极,石墨毡在较高的电极电位下仍能对苯酚保持较高电催化活性。采用粒子串的填充方式能降低反应器内短路电流、提高电流效率,反应器的时空产率从2.27 g/(m3·h)提升至6.47 g/(m~3·h)。周期交替电极极性对苯酚最终去除率影响较低,通过SEM扫描发现苯酚聚合物及其他污染物在纤维表面的沉积得到抑制。在苯酚初始质量浓度为100 mg/L、p H值为8~10、槽电压为8 V、电极极性交替周期为5 min、粒子电极采用串填方式、HRT为120 min的条件下,苯酚去除率大于90.3%。     

超重力-电催化耦合法降解含酚废水

将自制的超重力多级同心圆筒电解装置应用于电催化降解含酚废水的过程中, 解决电化学法处理废水存在"气泡效应"和"传质受限"导致的废水处理效率降低的难题。考察了超重力因子、电流密度、电解时间、电解质浓度、液体循环流量、苯酚初始浓度对废水降解效果的影响, 确定了超重力-电催化耦合法处理含酚废水的最佳工艺条件。结果表明:超重力因子为30、电流密度为200A/m²、电解质浓度为3g/L、液体循环流量为80L/h、电解时间为7h时, 处理初始浓度100mg/L的含酚废水, 苯酚去除率可达99.1%, COD去除率可达24.7%。超重力电催化法强化了离子传质过程, 实现了废水中苯酚的高效去除, 为含酚废水的处理研究探索了一种新途径。     

Catalytic ozonation with non-polar bonded alumina phases for treatment of aqueous dye solutions in a semi-batch reactor

Semi-batch experiments were conducted to investigate the effects of catalyst type, pH, initial dye concentration and production rate of ozone on the catalytic ozonation of the dyes, namely Acid Red-151 (AR-151) and Remazol Brilliant Blue R (RBBR). The used catalysts were alumina, 25% (w/w) perfluorooctyl alumina (PFOA), 50% (w/w) PFOA and 100% (w/w) PFOA. The results showed that the overall percent dye removal after 30 min of the reaction was not affected significantly by the catalyst type. However, highest COD reduction was achieved by ozonation with alumina for AR-151, and 100% PFOA for RBBR at pH 13. The behavior of COD reduction with the increasing amount of perfluorooctanoic (PFO) acid amount can be explained by the enhancement of catalytic activity of PFOA with alkyl chains. For both of the dyes, the highest dye and COD removals were reached at pH 13. The overall dye reduction after 30 min of ozonation was almost independent of the initial dye concentration at relatively low values while at the higher concentrations, it changed with the initial dye concentration for both of the dyes. Similarly, COD reduction changed on a limited scale with the increasing initial dye concentration from 100 mg/L to 200 mg/L; however, an increase of initial dye concentration to 400 mg/L decreased the COD reduction significantly. All the studied production rates of ozone were sufficient to provide almost 100% dye removal in 30 min, whereas the COD removal percentage was increased gradually by the increasing ozone input to the reactor. The reaction kinetics for the ozonation of each dye with and without catalyst was investigated and discussed in the paper.     

Modeling of a continuous electrochemical tubular reactor for phenol removal

In this study, the treatment of highly polluted synthetic phenolic wastewater in a tubular continuous electrochemical reactor was modeled and solved by the finite difference method. The reaction conditions were previously optimized with batch reactor experiments, and the synthetic wastewater containing 443 mg/L and 3063 mg/L initial phenol concentrations was treated in the runs at 25°C with 120 g/L electrolyte concentration. For the model solution, the column was divided into 10 nodes in z-direction and 9 nodes in r-direction with the intervals j z=3.5 cm, j r=0.5 cm, and j t=10 s and 1.2 min for 443 mg/L and 3063 mg/L phenol feed concentrations, respectively. The results of the model solution correlated with the experimental data fairly well, which could be useful in the design and scale up of tubular continuous electrochemical reactors for phenol removal.     

Post-Treatment of Composting Leachate by Ozonation

The post-treatment of composting leachate via an ozonation process in laboratory scale was studied in batch mode. According to the experiments, the COD removal was 47% after 30 min of ozonation via 0.4 g/h ozone (equivalent to 2.8 mg O₃/mg COD removed) at pH 9. In this circumstance, the removal of color and turbidity was also 86% and 89%, respectively. Increasing the ozone mass flow rate higher than 0.4 g/h had no considerable effect on the process variables. However, increasing the reaction time had a significant effect on both the removal of color and on COD of the leachate. Experimental data indicated that complete removal of color and 51% removal of COD were achieved after about 40 min of ozonation via 0.4 g/h ozone (equivalent to 3.3 mg O₃/mg COD removed). The ozone consumption rate increased as the reaction progressed and reached 4.1 mg O₃/mg COD removed after 60 min.     

Application of activated carbon fiber (ACF) for arsenic removal in aqueous solution

The adsorption of arsenic from aqueous solution using activated carbon fiber (ACF) was investigated. Several series of experiments were conducted to investigate the effect of operating parameters such as equilibrium time, flow rate, and initial concentration that affect to the adsorption rate. Average removal efficiency was 24% for the initial arsenic concentration of 10 mg/L to 17 mg/L. Breakthrough point in ACF unit reached at 5 hours of the experimental operation for aqueous solution containing arsenic. Adsorption capacity of the filter was found to be 0.18 mg/mg of ACF. With the increase of flow rate there was a slight increase in the removal of arsenic. Field tests from thirty contaminated sites in Sonarang, Bangladesh have shown that the arsenic removal efficiency was only 13.0% in the single ACF unit, while it was increased upto 24.6% in two ACF units in series. Among the several fitting regression curves tested, three dimensional non-linear regressions gave over 90% fitting, while for other linear regression curves it was in the range of 5 to 92% depending upon the various operating parameters. Non-linear models described the relationships of C with C₀ and t better than the linear ones, and this model gives a good generalization of the kinetics of arsenic in ACF for the laboratory tested ranges.     

电生物反应器降解含Cr6+和Zn2+的高浓度苯酚废水

经驯化得到能适应含Cr^6＋和Zn^2＋离子的高浓度苯酚废水的功能菌,将其在电生物反应器内挂膜并进行废水处理。研究发现,该生物膜对苯酚的降解能力受电场条件的影响显著。与无外加电场情况相比,在最佳电场条件3．0V,17．7V／m和1．98A／m^2下,1200mg／L苯酚降解效率提高了113％。电场条件变化对Cr^6＋的去除效果几乎没有影响,但对Zn^2＋的去除影响显著。实验结果表明：IOL废水中的苯酚（2400mg／L）经65h即可完全降解,而Cr^6＋和Zn^2＋（50mg／L及125mg／L）经12h处理后,去除率分别达到99％和67％;与之相比,相同实验条件下处理不含重金属离子的苯酚废水仅需57h。